Advanced electro-active optic device

ABSTRACT

Optical devices having a dynamic aperture and/or an apodization mask are provided. The aperture and/or mask may be provided by one or more electro-active elements, and may be used in an ophthalmic device that that is spaced apart from but in optical communication with an intraocular lens, a corneal inlay, a corneal onlay, or a spectacle lens that provide an optical power.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No.12/035,779, filed Feb. 22, 2008, which claims priority from U.S. Ser.No. 60/902,866 filed on Feb. 23, 2007, U.S. Ser. No. 61/020,759 filed onJan. 14, 2008, U.S. Ser. No. 61/025,348 filed on Feb. 1, 2008, and U.S.Ser. No. 61/029,469 filed on Feb. 18, 2008, each of which isincorporated by reference in its entirety. This application claims thebenefit of U.S. Ser. No. 61/037,351 filed on Mar. 18, 2008 and U.S. Ser.No. 61/060,291 filed on Jun. 10, 2008, each of which is incorporated byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an intraocular optic, an intraocularlens, a corneal inlay, and a corneal onlay. More specifically, thepresent invention relates to an intraocular optic, an intraocular lens,a corneal inlay, and a corneal onlay having an apodization mask and/or adynamic aperture for increasing depth of field. The mask and/or aperturemay be in optical communication or integral with an ophthalmic lens thatat least partially corrects a conventional error (lower orderaberrations such as myopia, hyperopia, regular astigmatism, andpresbyopia) and/or a non-conventional error (such as higher orderaberrations) of a user's eye.

2. Description of the Related Art

There are two major conditions that affect an individual's ability tofocus on near and intermediate distance objects: presbyopia and aphakia.Presbyopia is the loss of accommodation of the crystalline lens of thehuman eye that often accompanies aging. In a presbyopic individual, thisloss of accommodation first results in an inability to focus on neardistance objects and later results in an inability to focus onintermediate distance objects. It is estimated that there areapproximately 90 million to 100 million presbyopes in the United States.Worldwide, it is estimated that there are approximately 1.6 billionpresbyopes. Aphakia is the absence of the crystalline lens of the eye,usually due to surgical removal during cataract surgery. In an aphakicindividual, the absence of the crystalline lens causes a complete lossof accommodation that results in an inability to focus on either near orintermediate distance objects. For all practical purposes, an individualwill get cataracts if he or she lives long enough. Furthermore, mostindividuals with cataracts will have a cataract operation at some pointin their lives. It is estimated that approximately 1.2 million cataractsurgeries are performed annually in the United States.

The standard tools for correcting presbyopia are reading glasses,multifocal ophthalmic lenses, and monocular fit contact lenses. Readingglasses have a single optical power for correcting near distancefocusing problems. A multifocal lens is a lens that has more than onefocal length (i.e., optical power) for correcting focusing problemsacross a range of distances. Multifocal lenses are used in eyeglasses,contact lenses, corneal inlays, corneal onlays, and intraocular lenses(IOLs). Multifocal ophthalmic lenses work by means of a division of thelens's area into regions of different optical powers. Multifocal lensesmay be comprised of continuous surfaces that create continuous opticalpower as in a Progressive Addition Lens (PAL). Alternatively, multifocallenses may be comprised of discontinuous surfaces that creatediscontinuous optical power as in bifocals or trifocals. Monocular fitcontact lenses are two contact lenses having different optical powers.One contact lens is for correcting mostly far distance focusing problemsand the other contact lens is for correcting mostly near distancefocusing problems.

The standard tool for correcting aphakia is an intraocular lens (IOL). Afirst type of IOL is a single vision or multifocal IOL that isnon-accommodating and cannot change its optical power. A second type ofIOL is an accommodating IOL that can alter its focusing power by way ofexample only, compression, translation, mechanical bending of a surface,or a combination of the above. Aphakia may also be corrected by using asingle vision IOL in one eye and a multifocal or accommodating IOL inthe other eye, or any combination thereof.

Alternate approaches are also being used to correct presbyopia. Oneapproach is a corneal inlay that provides a small, fixed diameteraperture. By way of example only, the ACI 7000 corneal inlay made byAcuFocus is approximately 3.8 mm in diameter, 10 μm thick, and containsan opaque annulus with a 1.6 mm diameter transparent opening. Thisopening acts to reduce the aperture of the human eye to a smallerdiameter than what is normally achievable by the natural constriction ofthe pupil.

As is well known in the art, limiting the diameter of the aperture of anoptical system increases the system's depth of field. Depth of field isthe distance in front of and behind the object plane that appears to bein focus on the image plane. Although an optical system can only providefor the precise focus of an object at the focal distance, in a systemwith increased depth of field, the decrease in sharpness on either sideof the focal distance is gradual. Therefore, within the depth of field,the blurring produced on the image plane is imperceptible under normalviewing conditions. An aperture is used to increase depth of field byeliminating at least a portion of the light rays which make a largeangle with the lens's optical axis (non-paraxial light rays).Non-paraxial light rays are only sharply focused when originating fromobjects located at the focal distance. For objects located at otherdistances, non-paraxial light rays have the highest deviation from theimage plane. By eliminating non-paraxial light rays, the deviation fromthe image plane is minimized and objects located within a fixed distanceof the focal distance (i.e., within the depth of field) appear in focus.

The small aperture counteracts some of the effects of presbyopia bycreating a larger range of distances that appear in focus and allowspresbyopes to conduct near vision tasks without the need for multifocalcontact or spectacle lenses. The ACI 7000 is manufactured frombio-compatible materials whose optical properties are static, such aspolyvinyldene fluoride or non-hydrogel microporous perflouroether, byway of example only. As such, once the inlay is placed within the corneaits refractive optical power is fixed.

The AcuFocus corneal inlay is designed to reduce the amount of lightwhich reaches the retina. Additionally, the inlay is usually only beimplanted in one eye as deleterious optical effects such as halos,doubling of vision, light scattering, glare, loss of contrastsensitivity, and/or reduction of light hitting the retina are too greatand may be unacceptable when the inlay is implanted in both eyes. Thesedeleterious effects are caused by the size of the inlay's aperture andoccluded annulus in relation to the size of the pupil. These effectsespecially occur at night when the pupil dilates.

Another approach for correcting presbyopia is corneal refractive surgeryin which one eye is corrected for far distance and the other eye iscorrected for near distance. Another approach is a corneal inlay thatprovides a multifocal effect using diffractive optics, for example.

However, each of these approaches for correcting presbyopia and/oraphakia has drawbacks. Of course, some of these drawbacks are moresevere than others. For example, while spectacle eyewear is capable ofcorrecting one's vision for far, near and intermediate distances, thisapproach requires wearing a device that takes away from one's naturalappearance. Also, in some cases, certain multifocallenses may cause theuser to perceive distortion and experience vertigo.

Approaches for correcting presbyopia and/or aphakia that include the useof contact lenses can cause discomfort and can also result in one ormore of: halos, doubling of vision, light scattering, glare, loss ofcontrast sensitivity, limited range of focus, and/or reduction of lighthitting the retina. Approaches that include the use of IOLs can resultin one or more of: light scattering, glare, halos, ghosting, loss ofcontrast sensitivity, limited range of focus, and/or reduction of lighthitting the retina.

These drawbacks, or compromises to one's vision, can be very problematicespecially, by way of example only, when driving at night, driving inthe rain, or working on a computer. Therefore, there is a need for asuperior mode of correction for presbyopia and/or aphakia.

BRIEF SUMMARY OF THE INVENTION

An ophthalmic device as described herein may include an aperture, aperipheral region, a first transparent electrode having a plurality ofpixel regions and a second transparent electrode disposed over the firsttransparent electrode, and an electro-active layer disposed between thefirst electrode and the second electrode, the electro-active layerincluding a material that allows for a variable transmission of light.The pixel regions may be individually addressable. The opticaltransmission of the aperture, the peripheral region, or both may beadjustable. The shape of the aperture may be adjustable to variousshapes and diameters, including shapes other than a circle, and theaperture may be positioned relative to the line of sight of a user ofthe device. The aperture also may be repositioned after the device hasbeen applied to the user's eye. The device may be worn binocularly bythe wearer, and may be capable of correcting higher order aberrations ofthe wearer's vision. When worn, the device may be fixed in positionrelative to the wearer's pupil.

An ophthalmic device as described herein may include an apodization maskconstructed from an electro-active, transparent substrate, where thesubstrate has at least one optical transmission property that isalterable by electrical activation. The adjustable optical transmissionproperty may be, for example, the index of refraction of the substrate,or the amplitude and/or phase of transmitted light. The device mayinclude a dynamic aperture, where the shape and size of the aperture maybe defined based on a modulation transfer function of the wearer's eye,and the geometry of the aperture may be remotely adjustable. Theapodization mask may provide a transmission profile, such as aphase/amplitude profile, associated with a retinal image quality fordistance vision and an ambient light level range. When worn, the devicemay be fixed in position relative to the wearer's pupil.

An ophthalmic device as described herein may include an apodization maskhaving a transparent substrate, where the substrate has at a refractiveindex gradient. The device may include a dynamic aperture which may beremotely adjustable. When worn, the device may be fixed in positionrelative to the wearer's pupil.

An ophthalmic device as described herein may include a substrate and aliquid crystal layer capable of altering the optical transmission of thedevice, typically by about 30%-99% upon electrical activation. Theliquid crystal layer may be pixilated, and the device may include acontroller capable of activating segments of the liquid crystal layer ina desired pattern. When worn, the device may be fixed in positionrelative to the wearer's pupil.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects and features of the invention will be understood and appreciatedmore fully from the following detailed description in conjunction withthe figures, which are not to scale, in which like reference numeralsindicate corresponding, analogous or similar elements.

FIG. 1 shows a cross section of a healthy human eye.

FIG. 2A shows an exploded cross-sectional side view of an electro-activeelement having a dynamic aperture.

FIG. 2B shows a collapsed cross-sectional side view of theelectro-active element of FIG. 2A.

FIG. 2C shows an exploded cross-sectional side view of an element havingan apodization mask.

FIG. 2D shows a collapsed cross-sectional side view of the element ofFIG. 2C.

FIG. 3A shows a plurality of electrode rings operable for creating adynamic aperture.

FIG. 3B shows an example of a dynamic aperture having pixilatedelectrodes operable for creating a dynamic aperture.

FIG. 3C shows an example of a dynamic aperture having pixilatedelectrodes operable for creating a dynamic aperture.

FIG. 3D shows an example of a dynamic aperture having pixilatedelectrodes operable for creating a dynamic aperture.

FIG. 4A shows an exploded cross-sectional side view of an electro-activeelement having a dynamic aperture.

FIG. 4B shows a collapsed cross-sectional side view of theelectro-active element of FIG. 4A.

FIG. 5 shows several arrangements of the electrode rings shown in FIG.3A herein the geometric center of a dynamic aperture may be repositionedrelative to the geometric center of one's pupil.

FIG. 6 shows a stack of five electro-active elements that may each beused for the different arrangements of ring electrodes shown in FIG. 5.

FIGS. 7A, 7B, and 7C show devices having a dynamic aperture which areuseful as a corneal inlay, or corneal onlay.

FIG. 8 shows an IOO located in an anterior chamber of an eye and inoptical communication with a healthy presbyopic crystalline lens.

FIG. 9 shows an IOO located in an anterior chamber of an eye and illoptical communication with an IOL.

FIG. 10 shows an IOO located in an anterior chamber of an eye and inoptical communication with an IOL that corrects for far distance visiononly.

FIG. 11 shows an IOO located in an anterior chamber of an eye and inoptical communication with an IOL that corrects for far distance visionand near distance vision.

FIG. 12 shows an IOO located ill a posterior chamber of an eye and illoptical communication with an IOL.

FIG. 13 shows an IOL having a dynamic aperture in the portion of the IOLclosest to the eye's pupil.

FIG. 14 shows an IOL having a dynamic aperture in the middle portion ofthe IOL.

FIG. 15 shows an IOL having a dynamic aperture in the portion of the IOLclosest to the eye's retina.

FIG. 16 shows a corneal inlay having a dynamic aperture in opticalcommunication with a healthy presbyopic crystalline lens.

FIG. 17 shows a corneal inlay having a dynamic aperture in opticalcommunication with an IOL.

FIG. 18 shows that during the day, or in light, when a user's pupil isconstricted, a sensor senses the increase of light and a controller maycause a dynamic aperture in an electro-active element to constrict.

FIG. 19 shows that at night, or in darkness, when a user's pupil isdilated, a sensor senses darkness and a controller may cause a dynamicaperture in an electro-active element to dilate or remain dilated.

FIG. 20 shows the normal operation of a sensor and controller that havebeen overridden in which a dynamic aperture in an electro-active elementis constricted for near distance tasks in dark lighting conditions eventhough a user's pupil is dilated.

FIG. 21 shows a folded optic or lens having one or more electro-activeelements.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, an electro-active element refers to a device with anoptical property that is alterable by the application of electricalenergy. The alterable optical property may be, for example, opticalpower, focal length, diffraction efficiency, depth of field, opticaltransmittance, tinting, opacity, refractive index, chromatic dispersion,or a combination thereof. An electro-active element may be constructedfrom two substrates and an electro-active material disposed between thetwo substrates. The substrates may be shaped and sized to ensure thatthe electro-active material is contained within the substrates andcannot leak out. One or more electrodes may be disposed on each surfaceof the substrates that is in contact with the electro-active material.The electro-active element may include a power supply operably connectedto a controller. The controller may be operably connected to theelectrodes by way of electrical connections to apply one or morevoltages to each of the electrodes. When electrical energy is applied tothe electro-active material by way of the electrodes, the electro-activematerial's optical property may be altered. For example, when electricalenergy is applied to the electro-active material by way of theelectrodes, the electro-active material's index of refraction may bealtered, thereby changing the optical power of the electro-activeelement.

The electro-active element may be embedded within or attached to asurface of an ophthalmic lens to form an electro-active lens.Alternatively, the electro-active element may be embedded within orattached to a surface of an optic which provides substantially nooptical power to form an electro-active optic. In such a case, theelectro-active element may be in optical communication with anophthalmic lens, but separated or spaced apart from or not integral withthe ophthalmic lens. The ophthalmic lens may be an optical substrate ora lens. A “lens” is any device or portion of a device that causes lightto converge or diverge (i.e., a lens is capable of focusing light). Alens may be refractive or diffractive, or a combination thereof. A lensmay be concave, convex, or planar on one or both surfaces. A lens may bespherical, cylindrical, prismatic, or a combination thereof. A lens maybe made of optical glass, plastic, thermoplastic resins, thermosetresins, a composite of glass and resin, or a composite of differentoptical grade resins or plastics. It should be pointed out that withinthe optical industry a device can be referred to as a lens even if ithas zero optical power (known as plano or no optical power). However, inthis case, the lens is usually referred to as a “plano lens”. A lens maybe either conventional or non-conventional. A conventional lens correctsfor conventional errors of the eye including lower order aberrationssuch as myopia, hyperopia, presbyopia, and regular astigmatism. Anon-conventional lens corrects for non-conventional errors of the eyeincluding higher order aberrations that can be caused by ocular layerirregularities or abnormalities. The lens may be a single focus lens ora multifocal lens such as a Progressive Addition Lens or a bifocal ortrifocal lens. Contrastingly, an “optic”, as used herein, hassubstantially no optical power and is not capable of focusing light(either by refraction or diffraction). The term “refractive error” mayrefer to either conventional or non-conventional errors of the eye. Itshould be noted that redirecting light is not correcting a refractiveerror of the eye. Therefore, redirecting light to a healthy portion ofthe retina, for example, is not correcting a refractive error of theeye.

The electro-active element may be located in the entire viewing area ofthe electro-active lens or optic or in just a portion thereof. Theelectro-active element may be located near the top, middle or bottomportion of the lens or optic. It should be noted that the electro-activeelement may be capable of focusing light on its own and does not need tobe combined with an optical substrate or lens.

FIG. 1 shows a cross section of a healthy human eye 100. The whiteportion of the eye is known as the sclera 110. The sclera is coveredwith a clear membrane known as the conjunctiva 120. The central,transparent portion of the eye that provides most of the eye's opticalpower is the cornea 130. The iris 140, which is the pigmented portion ofthe eye and forms the pupil 150. The sphincter muscles constrict thepupil and the dilator muscles dilate the pupil. The pupil is the naturalaperture of the eye. The anterior chamber 160 is the fluid-filled spacebetween the iris and the innermost surface of the cornea. Thecrystalline lens 170 is held in the lens capsule 175 and provides theremainder of the eye's optical power. A healthy lens is capable ofchanging its optical power such that the eye is capable of focusing atfar, intermediate, and near distances, a process known as accommodation.The posterior chamber 180 is the space between the back surface of theiris and the front surface of the retina 190. The retina is the “imageplane” of the eye and is connected to the optic nerve 195 which conveysvisual information to the brain.

A static (non-dynamic) small aperture may have the benefit of a largedepth of field but also has the detriment of decreased transmission oflight through the lens or optic. Likewise, a static large aperture mayhave the benefit of increased transmission of light through the lens oroptic but also has the detriment of a decreased depth of field.

An ophthalmic device (that may be a lens or an optic) may include anelectro-active element having a dynamic aperture. As used herein, adynamic aperture is an aperture having an alterable diameter. Theaperture diameter of the dynamic aperture may be capable of switchingbetween two or more diameters, for example, between a first diameter anda second diameter. The dynamic aperture may switch between diameterscontinuously (i.e., in a smooth transition) or discontinuously (i.e., indiscrete steps). The dynamic aperture may have a minimum non-zeroaperture diameter or may be capable of completely closing such that theaperture diameter is zero. The dynamic aperture may create apertureshaving a circular shape, an elliptical shape, or any shape.

A dynamic aperture may be capable of alternating between a decreasedsize for increased depth of field (and decreased transmission of light)and an increased size for increased transmission of light (and adecreased depth of field). The size of the dynamic aperture may bedecreased for near distance and/or intermediate distance vision when alarge depth of field is most beneficial to a user. The dynamic aperturemay be increased in size from the diameter appropriate for proper neardistance vision to a larger diameter appropriate for proper intermediatedistance vision. The dynamic aperture's diameter may be furtherincreased in size for proper far distance vision to provide for anincreased transmission of light since a large depth of field is notcritical for far distance vision.

As used herein, an aperture refers to a first region, typically at ornear the entrance pupil, that is encompassed by a second region, whichmay be annular, where the second region has at least one opticalcharacteristic different than the first region. For example, the secondregion may have a different optical transmission, refractive index,color, or optical path length than the first region. The second regionmay be referred to as a peripheral region. The optical properties ofeach region may remain constant within each region, or may vary based onthe radius of the region or another function. An apodization functionmay be used to describe the variation in one or more optical propertiesof one or both regions.

An apodization mask may be used to alter light entering a wearer's eye.As used herein, a mask refers to a device that includes a controllableaperture. In some configurations, the mask operates by modulating theamplitude, phase, or both of light that is transmitted into the eyethrough the aperture. The aperture may be a static or a dynamicaperture. The mask may be a static mask, i.e., may always provide thesame modulation of light such as where a static gradient of refractiveindex or optical transmittance is incorporated into a layer of thedevice, or it may be a dynamic mask that has an alterable index ofrefraction or optical transmittance.

As used herein, an intraocular optic (IOO) is an optic (havingsubstantially no optical power) that is inserted or implanted in theeye. An intraocular optic may be inserted or implanted in the anteriorchamber or posterior chamber of the eye, into the stroma of the cornea(similar to a corneal inlay), or into the epithelial layer of the cornea(similar to a corneal onlay), or within any anatomical structure of theanterior chamber of the eye. An intraocular optic has substantially zerooptical power and therefore cannot focus light. Rather, an intraocularoptic as described herein may have a dynamic aperture and may only becapable of providing an increased depth of field.

As used herein, an intraocular lens (IOL) is a lens (having opticalpower) that is inserted or implanted in the eye. An intraocular lens maybe inserted or implanted in the anterior chamber or posterior chamber ofthe eye, into the capsular sac, or the stroma of the cornea (similar toa corneal inlay), or into the epithelial layer of the cornea (similar toa corneal onlay), or within any anatomical structure of the eye. Anintraocular lens has one or more optical powers and may or may not alsohave a dynamic aperture. When the IOL has a dynamic aperture it may becapable of providing an increased depth of field.

As used herein, a corneal inlay is an optic (having substantially nooptical power) or a lens (having optical power) that is inserted orimplanted within the stroma of the cornea When referring specifically toa corneal inlay optic, the terms “corneal inlay optic” or “plano cornealinlay” may be used. When referring specifically to a corneal inlay lens,the terms “corneal inlay lens” or “focusing corneal inlay” may be used.As used herein, a corneal onlay is an optic (having substantially nooptical power) or a lens (having optical power) that is inserted orimplanted within the epithelium layer of the cornea. When referringspecifically to a corneal onlay optic, the terms “corneal onlay optic”or “plano corneal onlay” may be used. When referring specifically to acorneal onlay lens, the terms “corneal onlay lens” or “focusing cornealonlay” may be used.

An electro-active element having a dynamic aperture may be integral with(i.e., embedded within or attached to) a corneal inlay, a corneal onlay,an IOO, or an IOL. The IOO or IOL may be inserted or implanted in theanterior chamber or posterior chamber of the eye, into the stroma of thecornea (as a corneal inlay), or into the epithelial layer of the cornea(as a corneal onlay). The corneal inlay and corneal onlay may be eithera lens capable of focusing light (and therefore having an optical power)or an optic incapable of focusing light (and therefore havingsubstantially no optical power). Electro-active elements as describedherein may provide an increased depth of field, and may at leastpartially correct for a conventional and/or non-conventional error of auser's eye. Electro-active elements may be used in optical communicationwith one or more of the following devices which are capable of focusinglight and may at least partially correct for a conventional and/ornon-conventional error of a user's eye: a spectacle lens, a cornealinlay, a corneal onlay, or an intraocular lens. A dynamic aperture mayprovide for an increased depth of field and may be in opticalcommunication and/or integral with an ophthalmic lens (which may be asingle vision or multifocal lens) which corrects for refractive errors(such as presbyopia). A mostly continuous range of perceived focus fromnear distance to far distance may be achieved. For example, a dynamicaperture may provide increased depth of field which serves to provide acontinuous range of focus between the fixed or static corrective powersof the ophthalmic lens). The mostly continuous range of focus mayinclude the field from a near distance to a far distance, from a neardistance to an intermediate distance, from an intermediate distance to afar distance, or between any range of distances.

FIG. 2A shows an exploded cross-sectional side view of an electro-activeelement 200 having a dynamic aperture. FIG. 2B shows a collapsedcross-sectional side view of the electro-active element of FIG. 2A. Oneor more electro-active elements 200 may be usable in a corneal inlay, acorneal onlay, an IOO, or an IOL. If more than one electro-activeelement is used, the electro-active elements may be stacked one uponanother if there is proper insulation between the elements.

An electro-active element 200 may comprise two optical substrates 210 ormay be bound by two optical substrates. The two substrates may besubstantially flat and parallel, curved and parallel, or one substratemay have a surface relief diffractive pattern and the other substratemay be substantially smooth. The substrates may provide an optical poweror the substrates may have no optical power. Each substrate may have athickness of 200 μm or less and may be rigid or flexible. Example rigidsubstrate materials include glass and silicon. Example flexiblesubstrates include flexible plastic films. In general, thinnersubstrates allows for a higher degree of flexibility for theelectro-active element which may be important for lenses or optics thatare inserted or implanted into the eye. A continuous opticallytransparent electrode 220 that provides for an electrical ground may bedisposed on one of the substrates and one or more individuallyaddressable optically transparent electrodes 225 may be disposed on thesecond substrate. Electrodes 225 may determine the properties of thedynamic aperture such as the size, shape, and/or diameters of thedynamic aperture. Electrodes 220 and 225 may, for example, comprise atransparent conductive oxide, such as indium tin oxide (ITO) or aconductive organic material (such as PEDOT:PSS or carbon nano-tubes).The thickness of the optically transparent electrodes may be, forexample, less than 1 μm, but is preferred to be less than 0.1 μm. Theelectrodes 220 and 225 may be coated with an alignment layer 230.Alternatively, only one of the electrodes is coated with the alignmentlayer. An electroactive material 240 is disposed between the alignmentlayers. The thickness of the electro-active material may be between 1 μmand 10 μm, but is preferably less than 5 μm. The electro-active materialmay be a liquid crystalline (LC) material.

A controller 250 connects to the electrodes 220 and 225 by electricalconnections 255 and may generate an electric field between theelectrodes by applying one or more voltages to each electrode. Thecontroller may be part of the electro-active element, or it may belocated outside the electro-active element and connect to the electrodesusing electrical contact points in the electro-active element. Thecontroller may be connected to a power source, sensors, or any othernecessary electronics. In the absence of an electric field between theelectrodes, the liquid crystal molecules align in the same direction asthe alignment direction. In the presence of an electric field betweenthe electrodes, the liquid crystal molecules orient in the direction ofthe electric field. In an electro-active element, the electric field isperpendicular to the alignment layer. Thus, if the electric field isstrong enough, the orientation of the liquid crystal molecules will beperpendicular to the alignment direction. If the electric field is notstrong enough, the orientation of the liquid crystal molecules will bein a direction somewhere between the alignment direction andperpendicular to the alignment direction. It should be noted that thesubstrates may be as wide as or wider than the electrodes, alignmentlayers, and electroactive material.

The electro-active element may have an aperture 260 through which lightpasses and an annulus 270 in which light is absorbed and/or scattered. Achange in the size of the dynamic aperture is typically inverselyproportional to a change in the depth of field of the electro-activeelement and is dependent upon a change in the transmission of lightthrough the electroactive element, as is known in the art. The aperturemay be dynamic and may be capable of switching between one or morediameters. The annulus may be positioned at the peripheral edge of theelectro-active element or may be spaced from the peripheral edge. Theannulus may extend to the radial center of the electro-active element.The aperture may be positioned at the geometric center of theelectro-active element and may be capable of extending all the way tothe peripheral edge of the electro-active element, to a fixed distancefrom the peripheral edge, or to a radial distance from the geometriccenter of the electro-active element. The aperture also may be capableof being relocated such that the center of the aperture is not the sameas the geometric center of the electro-active element. The annulustypically frames the aperture and defines the inner and outer limits andthe size of the aperture. As is described in further detail herein, theaperture may be altered to achieve any of a continuous or discrete rangeof shapes and/or diameters.

The electro-active material may include a layer of liquid crystal dopedwith a dye material such as a dichroic dye. By doping the liquid crystalmolecules with the dye material, the dye molecules align themselves withthe liquid crystal molecules. The dye molecules are polar and rotate toalign with an applied electrical field. The optical absorption of thedye material depends on the orientation of the individual dye moleculeswith respect to an incident optical wave. In a deactivated state withhomogeneous (horizontal) alignment of the liquid crystal molecules, whenthe electric field between the electrodes is not strong enough, the dyemolecules align with the alignment layers and the absorption of lightthrough the liquid crystal is minimized or maximized, depending upon therelative orientation between the dipole moment and the direction oforientation of the dye molecule. In an activated state with homogeneous(horizontal) alignment of the liquid crystal molecules, when theelectric field between the electrodes is strong enough, the dyemolecules rotate and align with the orientation of the electric field,perpendicular to the alignment direction. In this orientation, theabsorption of light though the liquid crystal is minimized. The oppositemay be the case when a homeotropic (vertical) alignment of the liquidcrystal is used such that absorption is minimized in a deactivated stateand maximized in an activated state. A ferroelectric liquid crystallinematerial may also be used.

FIG. 2C shows an exploded cross-sectional side view of an opticalelement 2200 having an apodization mask. FIG. 2D shows a collapsedcross-sectional side view of the element of FIG. 2C. One or more opticalelements 2200 may be usable in a corneal inlay, a corneal onlay, an IOO,or an IOL. If more than one element is used, the elements may be stackedone upon another if there is proper insulation between the elements.

In one configuration, the apodization mask may include a single layer2210 that includes a refractive index gradient. For example, thesubstrate 2210 may include a layer of a transparent polymer or othermaterial that has a refractive index gradient, preferably of at least0.01 units/mm in at least one meridian. In such a configuration, theother elements 2200, 2250, 2255 may be omitted. This configuration maybe referred to as a static mask. As a specific example, the substrate2210 may include at least one layer of a material, such as a transparentpolymer, that includes a refractive index gradient. Preferably, thegradient is at least 0.01 units/mm in at least one meridian.

A dynamic apodization mask may include an electro-active element 2200having two optical substrates 2210 or that is bound by two opticalsubstrates. The two substrates may be substantially flat and parallel,curved and parallel, or one substrate may have a surface reliefdiffractive pattern and the other substrate may be substantially smooth.The substrates may provide an optical power or the substrates may haveno optical power. Each substrate may have a thickness of 200 μm or less.In general, thinner substrates allows for a higher degree of flexibilityfor the electro-active element which may be important in optics orlenses that are inserted or implanted into the eye. A continuousoptically transparent electrode 2220 that provides for an electricalground may be disposed on one of the substrates and one or moreindividually addressable optically transparent electrodes 2225 may bedisposed on the second substrate. Electrodes 2225 may determine theproperties of the dynamic mask by altering the refractive index atvarious parts of the mask. The electrodes 2220, 2225 may include atransparent conductive oxide (such as ITO) or a conductive organicmaterial (such as PEDOT:PSS or carbon nano-tubes). The thickness of theoptically transparent electrodes may be, for example, less than 1 μm,but is preferred to be less than 0.1 μm. The electrodes 2220 and 2225may be coated with an alignment layer 2230. Alternatively, only one ofthe electrodes is coated with the alignment layer. An electroactivematerial 2240 is disposed between the alignment layers. The thickness ofthe electro-active material may be between 1 μm and 10 μm, but ispreferably less than 5 μm. The electro-active material may be a liquidcrystalline material.

A controller 2250 connects to the electrodes 2220 and 2225 by electricalconnections 2255 and is capable of generating an electric field betweenthe electrodes by applying one or more voltages to each electrode. Insome configurations, the controller is part of the electro-activeelement. The controller also may be located outside the electro-activeelement and connects to the electrodes using electrical contact pointsin the electro-active element. The controller may be connected to apower source, sensors, or any other necessary electronics. In theabsence of an electric field between the electrodes, the liquid crystalmolecules align in the same direction as the alignment direction. In thepresence of an electric field between the electrodes, the liquid crystalmolecules orient in the direction of the electric field. In anelectro-active element, the electric field is perpendicular to thealignment layer. Thus, if the electric field is strong enough, theorientation of the liquid crystal molecules will be perpendicular to thealignment direction. If the electric field is not strong enough, theorientation of the liquid crystal molecules will be in a directionsomewhere between the alignment direction and perpendicular to thealignment direction. It should be noted that the substrates may be aswide as or wider than the electrodes, alignment layers, andelectroactive material.

The electro-active material may include a layer of liquid crystal dopedwith a dye material such as an electrochromic dye. By doping the liquidcrystal molecules with the dye material, the dye molecules alignthemselves with the liquid crystal molecules. The dye molecules arepolar and rotate to align with an applied electrical field. The opticalproperties of the dye material with respect to the eye depend on theorientation of the individual dye molecules with respect to an incidentoptical wave. In a deactivated state with homogeneous (horizontal)alignment of the liquid crystal molecules, when the electric fieldbetween the electrodes is not strong enough, the dye molecules alignwith the alignment layers and the index of refraction of the layer isunchanged by the dye. For example, the index of refraction in anunactivated region may be at a minimum. In an activated state withhomogeneous (horizontal) alignment of the liquid crystal molecules, whenthe electric field between the electrodes is strong enough, the dyemolecules rotate and align with the orientation of the electric field,perpendicular to the alignment direction. In this orientation, the dyealters the index of refraction of the region. For example, the index ofrefraction of an activated region may be at a maximum. The opposite maybe the case when a homeotropic (vertical) alignment of the liquidcrystal is used such that a deactivated state has a higher index ofrefraction an activated state has a lower index of refraction. Aferroelectric liquid crystalline material may also be used.

The liquid crystal may alter its refractive index over the visiblespectrum by at least 0.1 units upon electrical activation. As usedherein, the “visible spectrum” refers to light having a wavelength inthe range of about 400-750 nm. A liquid crystal (LC) layer may include aguest-host mixture capable of altering the optical transmission of lightupon electrical activation. As used herein, the optical transmission ofa layer or device refers to the percentage of light energy that istransmitted through the layer or device and not lost to absorption orscattering. Preferably, the mixture is capable of altering the opticaltransmission by at least about 30%-99% upon activation. The liquidcrystal layer may be pixilated as previously described, and may beelectrically addressable in discrete portions of at least about 0.25 μm²without affecting the response of adjacent portions. The liquid crystallayer may be controllable by a computerized device, such as a processorand associated software, which may be capable of arbitrarily addressingmultiple segments in a preprogrammed or adaptable manner. The softwaremay be permanently embodied in a computer-readable medium, such as aspecial-purpose chip or a general purpose chip that has been configuredfor a specific use, or it may be provided by a digital signal. Thesoftware may be incorporated into a digital signal processing unitembedded into a vision correcting device that includes the apodizationmask. The liquid crystal layer also may be configured or programmed togenerate a pattern that changes or modulates the amplitude, phase, orboth of light transmitted through the mask into the eye of the patientfitted with the mask or a vision-correcting device incorporating themask.

The liquid crystalline material in FIGS. 2A-2D may be a nematic liquidcrystal, a twisted nematic liquid crystal, a super-twisted nematicliquid crystal, a cholesteric liquid crystal, a smectic bi-stable liquidcrystal, or any other type of liquid crystalline material. An alignmentlayer is a thin film, which, by way of example only, may be less than100 nanometers thick and constructed from a polyimide material. The thinfilm is applied to the surface of substrates that comes into directcontact with liquid crystalline material. Prior to assembly of theelectro-active element, the thin film is buffed in one direction (thealignment direction) with a cloth such as velvet. When the liquidcrystal molecules come in contact with the buffed polyimide layer, theliquid crystal molecules preferentially lie in the plane of thesubstrate and are aligned in the direction in which the polyimide layerwas rubbed (i.e., parallel to the surface of the substrate).Alternatively, the alignment layer may be constructed of aphotosensitive material, which when exposed to linearly polarized 1Nlight, yields the same result as when a buffed alignment layer is used.

FIG. 3A shows a plurality of electrode rings 300 operable for creating adynamic aperture. The electrode rings may be useful as opticallytransparent electrodes 225 in the electro-active element 200. Theelectro-active material 240 may be a liquid crystal doped with adichroic dye. Electrode rings 300 may be composed of several annularshaped electrodes 310, 320, 330, and 340. Of course, fewer or moreelectrodes are possible. Each electrode is individually addressable. Thecenter of the electrode rings may be concentric relative to a papillaryaxis once the electro-active element is placed in or on the eye. Theinter-electrode gap may be approximately 5 μm to 10 μm but may besmaller. The inner diameter of electrode 310 is r1, the outer diameterof electrode 310 is r2, the outer diameter of electrode 320 is r3, theouter diameter of electrode 330 is r4, and the outer diameter ofelectrode 340 is r5. The inner diameter of each electrode may define adifferent aperture size.

An electrode may be “activated” if a sufficiently strong electric fieldis applied between the electrode and a ground electrode, if voltageabove a threshold is applied to the electrode, or if a condition issatisfied which places an electro-active material between the electrodeand the ground electrode in an activated state. An electrode may be“deactivated” if a sufficiently strong electric field is not appliedbetween the electrode and a ground electrode, if voltage below athreshold is applied to the electrode, or if a condition is satisfiedwhich places an electro-active material between the electrode and theground electrode in a deactivated state.

When a liquid crystalline material is used, the liquid crystallinematerial may be activated when a voltage above a threshold ofapproximately 10 volts is applied between the electrodes and may bedeactivated when a voltage below a threshold of approximately 10 voltsis applied between the electrodes. The electric power used is that ofapproximately 1 microwatt. It should be pointed out that the electricpotential can be, by way of example only, 1 volt or less, 5 volts orless, 10 volts or less, or over 10 volts.

To reduce power consumption, a bi-stable liquid crystalline material maybe used. A bistable liquid crystalline material may switch between oneof two stable states with the application of electrical power (with onestate being an activated state and the other state being a deactivatedstate). The bi-stable liquid crystalline material remains in the onestable state until sufficient electrical power is applied to switch thebi-stable liquid crystalline material to the other stable state. Thus,electrical power is only needed to switch from one state to the otherand not to remain in a state. The bi-stable liquid crystalline materialmay switch to a first state when +5 volts or more is applied between theelectrodes and may switch to a second state when −5 volts or less isapplied between the electrodes. Of course other voltages, both higherand lower, are possible.

If electrodes 310, 320, 330, and 340 are activated, an opaque annulus270 may be formed between r1 and r5 and aperture 260 will be formedbetween the center of the electrodes and r1. If electrode 310 isdeactivated, the opaque annulus will now be formed between the innerdiameter of electrode 320 and r5 and aperture 260 will now be formedbetween the center of the electrodes and the inner diameter of electrode320. If electrodes 310,320,330, and 340 are deactivated, there will beno opaque annulus 270 and aperture 260 will now be formed between thecenter of the electrodes and r5. The aperture may be increased by firstdeactivating electrode 310, then electrode 320, then electrode 330, andfinally electrode 340. The aperture may be decreased by first activatingelectrode 340, then electrode 330, then electrode 320, and finallyelectrode 310. Thus, as shown in FIG. 3A, there are 5 possible aperturestops. However, fewer or more aperture stops are possible. As in acamera, each aperture stop may provide an aperture having twice the areaof the next smallest aperture size. In other words, there may be asquare root of two relationship between the inner diameters of eachelectrode. Of course, other aperture sizes are possible. When fullyconstricted, the aperture diameter may be between approximately 1.0 mmand approximately 3.0 mm, and may preferably be between approximately1.0 mm and approximately 2.5 mm, and more preferably may be betweenapproximately 1.0 mm and approximately 2.0 mm. When fully dilated, theaperture diameter may be approximately 7.0 mm or larger. In someconfigurations, there may be no aperture (i.e., there is no annulus suchthat the pupil of the eye serves as the natural aperture) in dark or dimenvironments.

The outer edge of the annulus may extend further than the outer edge ofthe pupil (whether fully dilated or constricted). If there is a gapbetween the outer edge of the annulus and the outer edge of the pupildeleterious effects may occur such as, by way of example only, halos,light scattering, and reduction in contrast sensitivity.

Each of the electrode rings may be activated approximately at the sametime for an instantaneous change in the aperture. To produce a fading inand out effect which gradually reduces and enlarges the dynamicaperture, each of the electrode rings may be activated and/ordeactivated sequentially. For example, the outermost electrode ring maybe activated first and deactivated last and the innermost electrode ringmay be activated last and deactivated first. The electrodes may beactivated or deactivated in less than approximately 1 second, and may bepreferably activated or deactivated in less than approximately 0.5seconds.

The electrodes 225 may be a plurality of individually addressableelectrodes arranged in a grid. Each electrode may be referred to a“pixel” (the electrodes in this case may be referred to as “pixilated”).The pixel may be any size or shape. By selectively electricallyactivating or deactivating the pixels the aperture 260 and annulus 270may be formed.

Some or all of the annular electrodes may be pixilated, or variousportions of the electrode rings, an inner portion, or combinationsthereof may be pixilated. FIGS. 3B and 3C show examples of pixilatedelectrodes. For example, FIG. 3B, shows a configuration in which eachthe electrode rings 310, 320, 330, 340 and an inner region 301 arepixilated. In some configurations, the electrode rings may be activatedor deactivated as rings to provide an annulus of desired size, pixels inthe inner region may be activated or deactivated to provide an apertureof desired shape and/or size. As another example, FIG. 3C shows aconfiguration in which only the inner region 301 is pixilated, and theelectrode rings 310, 320, 330, 340 are not. By selectively activating ordeactivating the pixels, an arbitrary shape and size may be provided forthe annulus and aperture. As a specific example, by selectivelyactivating or deactivating the shaded pixels 303 in FIG. 3D, aroughly-oval aperture may be formed. The specific set of shaded pixelsis illustrative only, and other shapes and sizes may be formed byappropriate selection of pixels in the inner region and/or the electroderings. As described in further detail herein, a specific aperture and/orannulus may be defined to match a user's specific needs, such as tooptimize the modulation transfer function of the eye.

For example, an individual's subjective satisfaction with perceivedimage quality may be improved when the image quality is maximized over alow- to mid-frequency range. A subjective quality factor may be definedasSQF=∫ ₁₀ ⁴⁰∫₀ ^(2r)|τ(ƒ,θ)|d(log ƒ)dθSuch a function is described in further detail in E. M. Granger and K.N. Cupery, “An Optical Merif Function (SQF) which Correlates withSubjective Judgments,” Photogr. Sci. and Eng., v. 16 (3), 1972, p.221-30. It has been found that the specific size and shape of anaperture to provide desirable improvements in subjective vision may bedetermined by minimizing the merit function (SQF) based on computationof a visual performance metric, such as visual strehl as a function ofpupil size. Such a calculation may be performed using ray tracing of aspecific eye model. Specific examples of models suitable for performingthese calculations include the “Indiana Eye” model and the Liu Brennaneye model as known in the art.

FIG. 4A shows an exploded cross-sectional side view of an electroactiveelement 400 having a dynamic aperture. FIG. 4B shows a collapsedcross-sectional side view of the electro-active element of FIG. 4A.Similar to the electro-active element 200, electroactive element 400includes two optical substrates 210. A continuous optically transparentelectrode 220 that provides for an electrical ground may be disposed onone of the substrates and one or more individually addressable opticallytransparent electrodes 225 may be disposed on the second substrate.Electrodes 225 may determine the properties of the dynamic aperture suchas the size, shape, and/or diameters of the dynamic aperture. Theelectrodes 220 and 225 may be coated with an alignment layer 230. Thealignment layers have an alignment direction offset 90 degrees from eachother, but other values such as 180, 270, 360 degrees or more arepossible. An electroactive material 240 is disposed between thealignment layers. The electro-active material may be a liquidcrystalline material, preferably one of a nematic, cholesteric, orsmectic bi-stable liquid crystalline material. The liquid crystallinematerial may be doped with a dichroic dye and become a dichroic liquidcrystalline material. A controller 250 connects to the electrodes 220and 225 by electrical connections 255 and is capable of generating anelectric field between the electrodes. The electro-active element mayhave an aperture 260 through which light passes and an annulus 270 inwhich light is absorbed and/or scattered. The electro-active element 400may further include two polarizers 280 positioned on either side of theelectro-active material (e.g., exterior to the electrodes). Thepolarizers may also be located on the outer surfaces of the substrates(the electrodes are located on the innermost surface of the substrates).Each of the polarizers may have a direction of polarization parallel tothe director of the liquid crystal layer at their respective outersurfaces (i.e., parallel to the alignment direction of the closestalignment layer). The polarizers have relative directions ofpolarization offset by, for example, 90 degrees. Such offset polarizersmay be referred to as “crossed” polarizers.

In a deactivated state, when the electric field between the electrodesis not strong enough, the alignment layers orient the director of theliquid crystal layer to align with the polarizers at the outer surfaces.In this orientation, light entering the first polarizer (i.e., lightthat is polarized parallel to the polarization direction of the firstpolarizer) is rotated 90 degrees by the liquid crystal and can now passthrough the second polarizer (i.e., the light is now polarized parallelto the polarization direction of the second polarizer). Therefore, in adeactivated state the absorption of light through the electro-activeelement is minimized. In an activated state, when the electric fieldbetween the electrodes is strong enough, the liquid crystal moleculesalign with the orientation of the electric field, perpendicular to thealignment direction. In this orientation, light entering the firstpolarizer (i.e., light that is polarized parallel to the polarizationdirection of the first polarizer) is not rotated and is blocked by thesecond polarizer (i.e., the light is polarized orthogonal to thepolarization direction of the second polarizer). Therefore, in anactivated state the absorption of light though the liquid crystal ismaximized.

The electrode rings shown in FIGS. 3A-D may be useful as opticallytransparent electrodes 225 in the electro-active element 400. As above,if electrodes 310, 320, 330, and 340 are activated, opaque annulus 270will be formed between r1 and r5 and aperture 260 will be formed betweenthe center of the electrodes and r1. If electrode 310 is deactivated,the opaque annulus will now be formed between the inner diameter ofelectrode 320 and r5 and aperture 260 will now be formed between thecenter of the electrodes and the inner diameter of electrode 320. Ifelectrodes 310, 320, 330, and 340 are deactivated, there will be noopaque annulus 270 and aperture 260 will now be formed between thecenter of the electrodes and r5.

One drawback to using polarizing films may be that they typically absorbapproximately 50% of incident light. Therefore, utilizing such films inan actual device would limit the amount of light that reaches theretina. To counteract this effect, a region concentric with the annularelectrodes may be physically removed from one or both of the polarizers.The region removed may be or any size or shape, but in a preferredconfiguration is equal to the inner diameter of the smallest ringelectrode. By removing this central region, one or more polarizers maybe used while increasing the overall transmission through theelectro-active element. In this configuration, the functionality of thedynamic aperture is not affected and overall transmission is increased.Additionally, the transmission contrast ratio (the ratio between lighttransmitted through the aperture and light transmitted through theannulus) between the aperture and the annulus is increased therebymaking the dynamic aperture more efficient in providing depth of field.Instead of removing the region, the region may instead be composed of athinner or less efficient polarizing film used to increase transmission,thereby favoring performance in the transmitting state over the opaquestate. In each of these configurations, the transmission contrast ratiobetween the darkened area of the annulus and a region of the aperturemay be increased.

It is virtually impossible to have an implanted corneal inlay, cornealonlay, IOO, or IOL perfectly centered with the optical axis of the eye,because the eye is asymmetric in normal anatomic configuration. The mostdesired position of an implant is aligned with the central axis of thepupil. Nevertheless, approximately 0.1 mm or 0.2 mm decentration of theeye relative to the center of the eye's pupil must be anticipated evenunder normal anatomical circumstances.

FIG. 5 shows several arrangements of the electrode rings shown in FIG.3A in which the geometric center of a dynamic aperture may berepositioned relative to the geometric center of one's pupil.Arrangement A has the geometric center of the ring electrodes alignedwith the geometric center of the electro-active element's substrates.Arrangements B, C, D, and E have the geometric center of the ringelectrodes aligned to the left, to the right, above, and below,respectively, with the geometric center of the electro-active element'ssubstrates. Arrangements A, B, C, D, and E may each be utilized in aseparate electro-active element. FIG. 6 shows a stack of fiveelectro-active elements that may each be used for the differentarrangements of ring electrodes shown in FIG. 5. Each electro-activeelement is properly insulated from the other electro-active elements.The distance between the geometric center of the ring electrodes and thegeometric center of the substrates may be between approximately 0.0 mmand approximately 1 mm, and more preferably between approximately 0.0 mmand approximately 0.5 mm. It should be noted that other alignments atany angle between the two centers are possible. This may allow for theability to alter the center of the dynamic aperture by way of remoteadjustment after an implant has been surgically implanted. One or moreof the arrangements of ring electrodes may be activated to the exclusionof the other arrangement to re-align the center of the dynamic aperturerelative to the line of sight of the user. This is important in caseswhere an implant was surgically implanted out of alignment with the lineof sight of the user. Certain retinal diseases or trauma such as, by wayof example only, macular degeneration, retinal tears, or retinaldetachments may damage a region of the retina. This also may also beuseful for realigning the line of sight of the user away from a damagedregion of the retina to a healthy region of the retina.

The use of an aperture to block a part of the light entering the humanpupil to enhance depth of field of the eye, and/or to reduce the impactof off-axis stray light rays in creating halos and other visualartifacts may be considered special cases of the spatial modulation oflight entering the cornea. It has been found that additional visualbenefits may achieved by using other types of modulators. For example,it may be desirable to define other properties of an aperture inaddition to the size and shape to provide a desired visual effect, suchas for a given set of visual tasks. One way of doing so involves the useof an apodization mask to alter the phase and/or amplitude of lightentering the eye.

In configurations in which electrodes 225, 2225 are a plurality ofindividually addressable electrodes arranged in a grid, the individualpixels may be selectively activated or deactivated. For example, such aconfiguration may allow for relocation of the geometric center of theaperture 260 and annulus 270 relative to the geometric center of thesubstrates or the eye's pupil.

The devices illustrated in FIGS. 2A, 2B, and 3-7 also may include anapodization mask as described with reference to FIGS. 2C and 2D, whichmay be static or dynamic. In some configurations, the structuredescribed with respect to FIGS. 2C-2D may provided in addition to theother structures described. For example, the devices may include anadditional layer, such as of a transparent polymer, that incorporates arefractive index gradient, or it may include an additional electroactiveelement 2200 in addition to the other elements described, orincorporated with the other elements as would be understood by one ofskill in the art. As another example, the devices may include an layerthat has an alterable index of refraction when electrically activated,or a layer incorporating a liquid crystal that alters its refractiveindex upon electrical activation. An apodization mask also may beprovided by one or more of the layers described with respect to FIGS.2-7. For example, a substrate 210, 520 may provide a static or dynamicmask, such as by including a refractive index gradient or a layer havingan alterable index of refraction.

Phase amplitude variation may be introduced by using a refractive indexgradient across the pupillary aperture that causes a variation in theoptical path difference without affecting the level of defocus α. Thereare several parameters that may be varied across the pupillary apertureof an apodization mask as a function of the pupil radius r: therefractive index of the medium, the thickness of the material, theoptical transmission, and the edge geometry (e.g., single or double,depending on whether the mask is circular or annular). The mask may bestatic or dynamic. A dynamic mask is adjustable by application of anexternally applied force such as an electric potential.

A dynamic mask may be superior to a static mask in that as the targetdistance and illumination conditions change, the optics of the eyechanges to adapt these changes in the environment. For example, theaberrations and depth of focus of an accommodated eye (or partiallyaccommodated eye, for a presbyope) viewing a near object (targetdistance about 40 cm) are different for those of the same eye in itsunaccommodated state, when viewing an object at 20 feet or greater. Inparticular the depth of focus available to the eye will depend on thetype of vision correction provided to the patient, and therefore thedesign of the dynamic mask will complement the type and power of thevision correction device that the patient is already wearing, or isgoing to receive in addition to the mask. A preferred method offabricating a dynamic mask may involve the use of a transparent liquidcrystal layer hermetically encapsulated between two transparent sheetsof flexible acrylic polymers, synthesized to be biocompatible in anocular environment. Orientation of the liquid crystal layer byapplication of an electric field changes its refractive index. Themodulation of optical transmission in a dynamic mask may be preferablyprovided by using a guest-host liquid crystal system, in which anelectrochromic dye is incorporated into a transparent liquid crystal.

To diagnose and fit a patient with a dynamic mask, two measurements maybe performed: a measurement of the size of the natural pupil as afunction of ambient light level, and a measurement of the emergingwavefront of the eye fitted with the mask. A phase and amplitude profileof the mask suited to provide a desired retinal image quality (possiblyexcepting defocus) may be generated for distance vision over a range ofambient light levels. For example, the spatial frequency of a peak inthe OTF of the combined eye and dynamic aperture system may be matchedto the peak of the NCSF of the patient. The dynamic mask may beprogrammed to provide the appropriate correction based on thephase/amplitude profile when performing the intended visual tasks. Forexample, the mask may be entirely or partially inactive in brightoutdoor light or other situations in which the natural pupil closes,which could reduce the effectiveness of the mask. In case of a maskencapsulated in an IOO, IOL, corneal inlay or corneal onlay, the dynamicmask may be implanted prior to performing the appropriate measurementsand/or generating the phase/amplitude profile for the treated eye.

An electro-active element may be capable of switching between a firstoptical power and a second optical power. The electro-active element mayhave the first optical power in a deactivated state and may have thesecond optical power in an activated state. The electro-active elementmay be in a deactivated state when one or more voltages applied to theelectrodes of the electro-active element are below a first predeterminedthreshold. The electro-active element may be in an activated state whenone or more voltages applied to the electrodes of the electro-activeelement are above a second predetermined threshold. Alternatively, theelectro-active element may be capable of “tuning” its optical power suchthat the electro-active element is capable of providing a continuous, orsubstantially continuous, optical power change between the first opticalpower and the second optical power.

Electro-active lenses may be used to correct for conventional ornon-conventional errors of the eye. The correction may be created by theelectro-active element, by the optical substrate or the ophthalmic lens,or by a combination of the two.

One or more electro-active elements having a dynamic aperture and/or adynamic mask may be attached to or embedded within an optical perform,optic, or substrate that does not refract or diffract light for thepurposes of correcting vision errors of the eye and thus does notprovide focusing power. The electro-active element may be attached to orembedded within an ophthalmic lens that corrects for the user'srefractive error caused by natural anatomical conditions and/or causedby the removal of a cataract or healthy crystalline lens. The ophthalmiclens may also correct any or all of the user's conventional and/ornon-conventional errors of the eye. Thus, a dynamic aperture and/ordynamic mask may be integral with a focusing lens. Alternatively, anelectro-active lens may have a first electro-active element having adynamic aperture or dynamic mask. The first electro-active element or asecond electro-active element in optical communication with the firstelectro-active element may be capable of correcting any or all of theuser's conventional and/or non-conventional errors of the eye. The abovedevices may be a corneal onlay, a corneal inlay, an IOO, or an IOL, andmay be used in optical communication with a focusing lens such as, byway of example only, an IOL, a crystalline lens, a corneal inlay, acorneal onlay, or a spectacle lens. The focusing lens may be static(incapable of altering its optical power) or dynamic (capable ofaltering its optical power).

FIGS. 7A, 7B, and 7C show optical devices having a dynamic aperturewhich are useful as a corneal inlay, or corneal onlay. The devices shownin FIGS. 7A, 7B, and 7C may be modified slightly, for example by addingstabilizing haptics, for use as an anterior or posterior chamber IOO orIOL having a dynamic aperture. Optic or lens 500 may have one or moreelectro-active elements 510. Electro-active element 510 may be similarto electro-active elements 200 or 400 or may not have a dynamic apertureand/or apodization mask and may instead provide a changeable opticalpower. The electro-active element may be embedded within or attached tosubstrates 520. The substrates may have no optical power or may have oneor more optical powers. The substrates and/or the electro-activeelements may be capable of correcting for at least a portion of any orall conventional and/or non-conventional error of the eye. A controller530 may be electrically connected to the electrodes in theelectro-active elements by electrical connections 535. The electrodesmay define a mostly transparent aperture 540 and a mostly opaque annulus545. The term “mostly transparent” means approximately 50% or moreoptical transmission (and preferably 75% or more) and isn't meant tonecessarily mean 100% optical transmission. The term “mostly opaque”means approximately 50% or less optical transmission (and preferably 35%or less) and isn't meant to necessarily mean 0% optical transmission.

The substrates may have one or more openings 550 and/or pores 555 toallow nutrients and/or cellular waste products to pass through thesubstrates and/or the electro-active elements. The openings and/or poresmay be created, by way of example only, by a laser, or they may bemachined or stamped. Typically, the openings and pores are located atnon-electrical or otherwise non-critical areas of the lens or optic suchas within a central region where the electrodes do not extend or applypower. These features are especially important when the lens or optichaving a dynamic aperture is used as a corneal inlay or corneal onlay.

The controller may draw at least some of its electrical power from apower supply 560. The power supply may be attached and integral with thesubstrates or attached but not integral with the substrates. The powersupply may be a thin film rechargeable battery such as thosemanufactured by Excellatron. The thin film rechargeable battery may becapable of being cycled in excess of 45,000 cycles. This may provide ausable lifetime of 20-25 years in the lens or optic. Two thin filmrechargeable batteries may be used and may stacked one atop the other.In this configuration, one of the batteries may be used for 20-25 yearsand the other battery may be switched to when the first battery is nolonger operable. Alternatively, the other battery may be switched to bya signal sent remotely to the controller. This may extend the lifetimeof the optic or lens to 40-50 years. The power supply may also be acapacitor. The power supply may be remotely charged, by way of exampleonly, by induction.

A light-sensitive cell 565 and piezo-electric materials may also be usedto supplement and or augment the power supply's electrical power.Alternatively, the light sensitive cell and/or the piezoelectricmaterials may obviate the need for a power supply. The light-sensitivecell may be a solar cell. Alternatively, the light-sensitive cell may bea 1.5 μm photovoltaic cell. The photovoltaic cell is utilized andlocated out of the line of sight of the user and more preferablyutilized and located peripheral to the margin of the pupil whenpartially dilated by darkness, but not fully dilated. The lens or opticmay thus be charged by using an eye safe laser capable of energizing the1.5 μm photovoltaic cell or cells. The user may position his or her chinand forehead into a device that provides the eye safe laser energyneeded to energize the 1.5 μm photovoltaic cell or cells. This may beaccomplished at home once a day or as needed. The proper energy can beprovided through a normally dilated pupil or a fully non-medicateddilated pupil caused by a very dark room or by the device blocking outany ambient visible light. When utilizing a 1.5 μm photovoltaic cell orcells within the lens or optic, the cell or cells in may need to becapable of bending. When using a 1.5 μm photo-voltaic cell not capableof bending, multiple cells are used and are placed in a pattern thatallows for folding or rolling the lens or optic over or around the cellsprior to insertion into the eye.

The light-sensitive cell 565 may be a solar cell. The solar cell may belocated in front of (closer to the cornea of the eye) and separatelydisposed from a portion of the iris of a user's eye. Thin electricalwiring may operably connect the solar cell to the controller of theoptic or lens. The electrical wiring may pass through the pupil withouttouching the iris and operably connect to the IOO or IOL in the anterioror posterior chamber of the eye. The solar cell may be large enough suchthat it supplies enough electrical power to obviate the need for aseparate power supply. The thin electrical wiring may not conductelectricity and may have a form factor which has the appropriate tensilestrength to hold the solar cell in place. In some configurations, one ormore small holes may be made in the iris by an ophthalmic laser suchthat the thin electrical wiring connects the solar cell to the IOO orIOL that houses an electro-active element.

A lens or optic as described herein may include a memory metal material570 for re-establishing the proper shape, positioning and alignment ofthe device after being folded and inserted into an eye. A memory metal“remembers” its shape and attempts to regain its original geometry afterbeing deformed (for example, while being folded in preparation forinsertion into the eye). The memory metal may also function as anantenna for inductively charging the lens or optic or for receivingsignals from a transmitter. The transmitter may send a signal to thelens or optic to change the diameter of the dynamic aperture or tochange the lens's optical power.

A sensor 580 may be included. The sensor may be a range finder fordetecting a distance to which a user is trying to focus. The sensor maybe light-sensitive cell 565 for detecting light that is ambient and/orincident to the lens or optic. The sensor may include, for example, oneor more of the following devices: a photo-detector, a photovoltaic or UVsensitive photo cell, a tilt switch, a light sensor, a passiverange-finding device, a time-of-flight range finding device, an eyetracker, a view detector which detects where a user may be viewing, anaccelerometer, a proximity switch, a physical switch, a manual overridecontrol, a capacitive switch which switches when a user touches the nosebridge of a pair of spectacles, a pupil diameter detector, a bio-feedback device connected to an ocular muscle or nerve, or the like. Thesensor may also include one or more micro electro mechanical system(MEMS) gyroscopes adapted for detecting a tilt of the user's head orencyclorotation of the user's eye.

The sensor may be operably connected to the controller. The sensor maydetect sensory information and send a signal to the controller whichtriggers the activation and/or deactivation of one or more dynamiccomponents of the lens or optic. When a lens or optic includes anelectro-active element having a dynamic aperture and/or apodizationmask, the sensor, by way of example only, may detect the intensity oflight and communicate this information to the controller. The sensor maybe a photo-detector and may be located in a peripheral region of thelens or optic and located behind the iris. This location may be usefulfor sensing increases and/or decreases in available light caused by theconstriction and dilation of the user's pupil. FIG. 19 shows that atnight, or in darkness, when the user's pupil is dilated, the sensorsenses darkness and the controller may cause the dynamic aperture todilate or remain dilated. FIG. 18 shows that during the day, or inlight, when the user's pupil is constricted, the sensor senses theincrease of light and the controller may cause the dynamic aperture toconstrict. A dynamic aperture may remain constricted until the sensorsenses darkness or the lack of available light below a certain thresholdin which case the controller may cause the dynamic aperture to dilate.The sensor may be located in any region of the lens or optic that worksin an optimum manner. The controller may have a delay feature whichensure that a change in intensity of light is not temporary (i.e., lastsfor more than the delay of the delay feature). Thus, when a user blinkshis or her eyes, the size of the aperture will not be changed since thedelay of the delay circuit is longer than the time it takes to blink.The delay may be longer than approximately 0.0 seconds, and preferably1.0 seconds or longer.

The sensor, by way of example only, may detect the distance to which oneis focusing. If the sensor detects that a user is focusing within a neardistance range, the controller may cause the dynamic aperture toconstrict to produce an increased depth of field. If the sensor detectsthat the user is focusing beyond the near distance range, the controllermay cause the dynamic aperture to dilate. The sensor may include two ormore photo-detector arrays with a focusing lens placed over each array.Each focusing lens may have a focal length appropriate for a specificdistance from the user's eye. For example, three photo-detector arraysmay be used, the first one having a focusing lens that properly focusesfor near distance, the second one having a focusing lens that properlyfocuses for intermediate distance, and the third one having a focusinglens that properly focuses for far distance. A sum of differencesalgorithm may be used to determine which array has the highest contrastratio (and thus provides the best focus). The array with the highestcontrast ratio may thus be used to determine the distance from a user toan object the user is focusing on.

Some configurations may allow for the sensor and/or controller to beoverridden by a manually operated remote switch. The remote switch maysend a signal by means of wireless communication, acousticcommunication, vibration communication, or light communication such as,by way of example only, infrared. By way of example only, should thesensor sense a dark room, such as a restaurant having dim lighting, thecontroller may cause the dynamic aperture to dilate to allow more lightto reach the retina. However, this may impact the user's ability toperform near distance tasks, such as reading a menu. The user couldremotely control the dynamic aperture of the lens or optic to constrictthe aperture to increase the depth of field and enhance the user'sability to read the menu. FIG. 20 shows the normal operation of a sensorand controller that have been overridden in which a dynamic aperture isconstricted for near distance tasks in dark lighting conditions eventhough the user's pupil is dilated. When the near distance task hascompleted, the user may remotely allow the sensor and controller tocause the aperture to dilate once again automatically thereby allowingthe user to see best in the dim restaurant with regard to non-neardistance tasks. When activated, the remote switch signal may bereceived, by way of example one, by the lens or optic via an antennaformed from the memory metal material 570.

The substrates described herein may be coated with materials that arebiocompatible with anatomical objects in the eye. Biocompatiblematerials may include, for example, polyvinyldene fluoride ornon-hydrogel microporous perflouroether. The substrates and the variouselectronics that are affixed to or embedded within the substrates mayoptionally be overcoated to be hermetically sealed to prevent or retardleaching. Additionally, the substrates may be designed to encapsulatethe various electronics such that they are buried within the substrates.

The lenses and optics described herein may be bendable, foldable, and/orable to be rolled up for fitting during insertion through a smallapproximately 1 mm to 3 mm incision. A syringe-like device commonly usedfor implantation of IOLs having a piston may be used as an insertiontool that allows for a folded or rolled lens or optic to be placedproperly where desired in either the anterior or posterior chamber ofthe eye. FIG. 21 shows a folded optic or lens having one or moreelectro-active elements.

Optical devices having a dynamic aperture and/or an apodization mask canbe fit or implanted either monocularly (in only one eye of a user) orbinocularly (in both eyes of a user). Because the dynamic aperture canbe programmed to expand to a larger size at night or in dim lightingconditions when the pupil diameter of the user would naturally dilate,glare, halos, ghosting, and reduced light hitting the retina of the userare largely eliminated. In contrast to other IOLs, corneal onlays, andcorneal inlays that do not have a dynamic aperture and are thereforesometimes fit for far distance correction in one eye and near distancecorrection in the other eye as a compromise due to glare, halos,ghosting, etc., the lenses and optics described herein allow for abinocular approach. It should be pointed out that the optics and lensesdescribed herein can also be implanted or fit in monocular manner, ifdesired, and can be designed and fabricated in such a way that thecentral point of the dynamic aperture and/or mask may be remotelyrelocated relative to the center of the optic or lens after beingimplanted within or on the eye in order to better align the central axisof the dynamic aperture to the user's line of sight.

An optic or lens having a dynamic aperture and/or an apodization maskmay be used in optical communication with a healthy but presbyopiccrystalline lens, an underperforming or fully performing single focusIOL, static multifocal IOL, dynamic focusing IOL (such as that of anelectro-active focusing IOL), or an accommodating IOL without a dynamicaperture, an eye having an iris that has been traumatized and is tom,has a hole, or does not contract or dilate properly, an iris devoid ofpigment such as an iris of certain albinos, a fully performing orunderperforming multifocal or single vision corneal inlay or cornealonlay without a dynamic aperture, a fully performing or underperformingmultifocal or single vision spectacle lens without a dynamic aperture,or an eye that has had underperforming refractive surgery.

A “fully performing” lens is capable of properly focusing light on theretina. An “underperforming” lens is not capable of properly focusinglight on the retina. In most cases, an optic or lens having a dynamicaperture and/or apodization mask will improve the quality of visualacuity as perceived by the user when used in association with and inoptical communication with the various examples provided in thepreceding paragraph. When used with a fully forming lens, a dynamicaperture increases the depth of field and acts to inhibit or remove someor most of the higher aberrations of a user's eye.

A lens or optic that houses an electro-active element as disclosedherein can be comprised of ophthalmic materials that are well known inthe art and used for IOLs, or corneal inlays. The materials can beflexible or non-flexible. For example, an IOO may be made from twoapproximately 100 μm layers of, for example, a polyether, a polyimide, apolyetherimide, or a polysulphone material having the appropriateelectrodes, liquid crystalline material (which may be doped with adichroic dye), optional polarizing layers, power supply, controller,sensor and other needed electronics. Each 100 μm layer is used to form aflexible envelope that sandwiches and houses the electronics andelectro-active material. The total thickness of the working optic isapproximately 500 μm or less. The outer diameter of is approximately 9.0mm (not including any haptics). The IOO may be capable of being foldedand inserted into the eye through a small surgical incision ofapproximately 2 mm or less. In some configurations, a thin layer ofmemory metal is utilized as part of the IOO to aid in opening the IOO toits proper shape and location after it has been inserted into the eye'santerior or posterior chamber.

A tint or a filter may be incorporated into a lens or optic to filterhigh energy blue light and/or ultra-violet light. The filter or tint mayalso be used to enhance contrast sensitivity as perceived by the user.

The diameter of the IOO or IOL may be between approximately 5 mm andapproximately 10 mm (not including haptics), depending upon the lens'sor optic's intended application. Other dimensions are possible as well

When used as a corneal inlay, the diameter of an optic or lens having adynamic aperture and/or apodization mask must be less than the diameterof the cornea. In some configurations, the optic or lens can have adiameter between approximately 5 mm and approximately 14 mm. The outersurface of the substrates may be curved to substantially match thecurvature of the cornea, such as when used in a corneal inlay, or tomatch any other desired curvature, or the outer surface of substratesmay be planar.

FIG. 8 shows an IOO 800 located in an anterior chamber of an eye and inoptical communication with a healthy presbyopic crystalline lens 810.The IOO may include a dynamic aperture, a dynamic mask, or both. Inconfigurations including a dynamic aperture, the IOO may provide forimproved intermediate and near vision by increasing the depth of focus.FIG. 9 shows an IOO 900 located in an anterior chamber of an eye and inoptical communication with a far and near vision IOL 910. The IOO mayinclude a dynamic aperture, a dynamic mask, or both. An IOO including adynamic aperture may provide for increased depth of focus. FIG. 10 showsan IOO 1000 located in an anterior chamber of an eye and in opticalcommunication with an IOL 1010 that corrects for far distance visiononly. The IOO may include a dynamic aperture, a dynamic mask, or both.The configuration shown in FIG. 10 may be useful for providing anincreased depth of field for providing near distance and/or intermediatedistance correction by way of a dynamic aperture. FIG. 11 shows an IOO1100 located in an anterior chamber of an eye and in opticalcommunication with an IOL 1110 that corrects for far distance vision andnear distance vision. The IOO may include a dynamic aperture, a dynamicmask, or both. A dynamic aperture may be useful for providing anincreased depth of field for providing intermediate distance correction.FIG. 12 shows an IOO 11200 ocated in a posterior chamber of an eye andin optical communication with an IOL. The IOO may include a dynamicaperture, a dynamic mask, or both. FIG. 13 shows an IOL 1310 having adynamic aperture in the portion of the IOL closest to the eye's pupil.The IOL also may include a dynamic mask. FIG. 14 shows an IOL having adynamic aperture in the middle portion of the IOL. The IOL also mayinclude a dynamic mask. FIG. 15 shows an IOL having a dynamic aperturein the portion of the IOL closest to the eye's retina. The IOL also mayinclude a dynamic mask. FIG. 16 shows a corneal inlay in opticalcommunication with a healthy presbyopic crystalline lens. The inlay mayinclude a dynamic aperture, a dynamic mask, or both. FIG. 17 shows acorneal inlay in optical communication with an IOL. The inlay mayinclude a dynamic aperture, a dynamic mask, or both. It should be noted,that it is not possible to show all possible configurations,embodiments, combinations, and placements of the present invention. Forexample, a corneal inlay having a dynamic aperture are not shown. Inaddition, a static or dynamic apodization mask may be incorporated intoan IOO, IOL, corneal only, coneal inlay, or other device as shown anddescribed, with or without a dynamic aperture. However, these will beapparent to those skilled in the art.

An IOO or IOL including a dynamic aperture and/or an apodization maskcan be surgically inserted during the initial surgical procedure thatinserts a conventional IOL without a dynamic aperture. Alternatively,the IOO or IOL may be surgically inserted as a follow on surgicalprocedure hours, days, weeks, months, or years after the initial IOLsurgery.

Successful operation of a lens or optic including a dynamic aperture isdependent upon obtaining the maximum allowable transmission through themostly transparent aperture and the minimum allowable transmissionthrough the mostly opaque annular region. Experiments were conductedwith neutral density (ND) optical filters with ND values between 0 and1.0 in which holes having a 1.5 mm diameter were formed in the filtersto create apertures. In some experiments, a second filter was placedover the aperture to simulate the transmittance through the aperture.Neutral density is measure of light transmittance based on a logarithmicscale and is related to the transmission (T) via the followingrelationship:T=10^(−ND)  Equation 3

In the experiment, the filter was held in front of and very close to theeye of a non-corrected +2.50 D presbyopic patient. The presbyopicpatient looked at a near vision target at approximately 13 inches fromthe patient's eye through the aperture. It was discovered that such anaperture works for increasing depth of field by providing good visualacuity and contrast sensitivity, but only under certain conditions.

In general, the best results were obtained when the ND value of themostly transparent aperture was less than approximately 0.1 (T greaterthan approximately 80%) and the difference in ND values between themostly transparent aperture and the mostly opaque annulus was greaterthan approximately 0.3. In a preferred configuration, the ND value forthe mostly transparent aperture may be less than approximately 0.04 (Tgreater than approximately 90%) and the ND of the mostly opaque annulusis greater than approximately 1.0 (T less than approximately 10%). Whileincreasing the difference in ND values between the mostly transparentaperture and the mostly opaque annulus can compensate for a high NDvalue in the mostly transparent aperture, it will lead to an undesirabledecrease in overall transmission of light to the retina.

The optical effects believed to result from use of an aperture and/orapodization mask will now be described. Retinal image quality can bequantitatively described by an optical transfer function (OTF) that isthe plot of the value of the complex contrast sensitivity function as afunction of the spatial frequency of the target object. A complexcontrast sensitivity function can be used to characterize the imagequality because the optics of the eye may change the spatial frequencyof the image relative to that of the target, dependant on the targetspatial frequency, in addition to reducing the contrast of the image. Inprinciple, an OTF can be constructed for every object distance andillumination level. The OTF of the eye varies with object distance andillumination level, because both of these variables change the optics ofthe eye. The OTF of the eye may be reduced due to refractive errors ofthe eye, ocular aberrations or loss of accommodative ability due toonset of presbyopia.

The image of a point object is the Fourier transform of the apertureconvoluted with the modulation transfer function (MTF) of the imagingoptics, where the MTF is the real component of the OTF discussed aboveand shown in Equation 1. The resulting point image is known as the pointspread function (PSF), and may serve as an index of measurement of thequality of the ocular optic (i.e., a bare eye or eye corrected with avision care means). The PSF of the retinal image is found to correlatewith the quality of visual experience, especially when it is compromisedby halos or glint or other image artifacts. Thus, a systematic approachmay be applied to designing an aperture by using a pupil apodizationfunction. Such a function may be consistent with other previousrepresentations of an aperture, such as that published by Guyon (Guyon,O, “Phase-induced amplitude apodization of Telescope Pupils inExtrasolar Terrestrial Planet Imaging”, Astron & Astrophys, 401 (2003);pp 379) shown in Equation 1:Ψ_(O)(x)=Ψ_(E)(x)−Ψ_(E)(x)×M^(x)  Equation 1In which Ψ_(O)(x) and Ψ_(E)(x) represent the complex amplitudes of theentrance and exit pupils, respectively, M^(x) represents the Fouriertransform of the mask shape, and x represents a convolution.

Similar formulations of apertures are described in, for example,Martinache F, “A Phase-Induced Zonal Zernicke Apodization Designed forStellar Coronagraphy”, in J Opt A., Pure Appl Opt, 6 (2004), pp 809-814.The apodization function may be used to introduce defocus as describedin U.S. Pat. No. 5,980,040 by introducing an apodization function or anaperture that alters the amplitude of the wavefront as a function of thepupillary radius. It is also possible to introduce an artificialaperture that alters the phase of the wavefront as a function ofpupillary radius, having a beneficial impact on the PSF. A quadraticphase distribution leaving the real amplitude of the apodizationfunction unchanged can lead to defocus, e.g.,Ψ_(E)(x)=Π(x)e ^(−iαx2)  Equation 2at the entrance pupil, with Π(x)=1, if |x|≦½ and 0 otherwise, where α isa parameter representing the amount of defocus.

Therefore, to match the aperture to a given set of visual tasks, thegeometry and optical properties of the aperture may be relative to adesired PSF for the set of visual tasks. To do so, the retinal imagequality (for example, as defined by the PSF, or the OTF of the ocularsystem) may be matched to the visual perception experienced by anindividual. Visual perception may be characterized by the neuralcontrast sensitivity function (NCSF). One step in the translation of aretinal image to a visual perception is the neuronal transfer of “visualinformation,” i.e., the electrical signals produced by the retinalphotoreceptors on receiving the image on the fovea. The neuronaltransfer process is subject to noise, which can cause a degradation ofimage contrast in this case. The efficiency of neuronal transfer can beexpressed as a function of a spatial frequency or a set of spatialfrequencies of the retinal image, retinal illuminance, and the locationof the point on the fovea with respect to the center of the exit pupil.Therefore, a maximum, optimum, or desirable aperture performance may beobtained by an aperture that can modulate the quality of the retinalimage such that the OTF of the combined optical system, including theaperture, has a peak value of contrast at a spatial frequency thatmatches the peak of the NCSF of a particular individual. Although thechromaticity of the viewed image may affect the relationship between theNCSF and perceived quality, the present disclosure does not considerthis factor, and provides an achromatic assessment of the retinal imagequality and its match to the NCSF.

Different variables may be used to change the performance of anaperture. For example, U.S. Pat. Nos. 5,786,883 and 5,757,458 to Milleret al. describe the effects of an annular aperture, apertures that havemultiple optical zones for different types of photoreceptors, andvariations in aperture size. In general, the depth of focus increasesand the retinal image quality improves as the aperture decreases insize. However, the total MTF of the combined eye and aperture system isdegraded with increased aperture size. In general, the improvement ofretinal image quality improves until the aperture size becomes about 2mm or less. Below this point, the effects of diffraction may overcomethe positive effect due to enhancement of the depth of field.

Two types of functional adjustments may be made within an aperture: theoptical path difference caused by at a point within the aperture as afunction of location (i.e., distance from the pupillary center and itsazimuth), and its optical transmission. For a two dimensional apertureorthogonal to the optic axis of the eye, a description of the opticaltransmission is provided by a pupil apodization function, as shown inEquation 2 for α=1. More generally, this is true for a two dimensionalaperture in another plane, since the aperture may be projected onto aplane orthogonal to the optic axis of the eye. Clinical benefits of thisapproach have been reported in, for example, Applegate R A, et al,“Aberrations and Visual performance, Part I, Optical and neural Limitsto Vision”, Presented at the Wavefront Congress, 2005, which describesthe MTF of the eye as a function of pupillary apertures. Application ofan aperture enhances the low spatial frequency MTF at the expense of thehigh spatial frequency values of the MTF function of the eye. In effect,the aperture functions as a low band pass spatial frequency filter.Since the NCSF of a normal human eye typically peaks at 4-8cycles/degree, this shift of MTF and associated OTF values of theretinal image enables the OTF to better match the NCSF of the eye. Aspreviously mentioned, improving image quality at low spatial frequenciesmay enhance visual comfort and the subjective quality of vision.

The pupil apodization described by Guyon and others relates toenhancement of the resolution of a telescope system. Their assumptionwas that the emerging wavefront from the star was extremely flat, and inno need of correction. When designing for a human visual system,wavefront aberrations may be corrected at the expense of the OTF at highspatial frequencies. That is, a lower optical resolution may beacceptable to approach an OTF of the human visual system that is peakedat mid to low spatial frequencies, and a PSF that is diffraction limitedat least for a few (1-3) Airy diameters (λ/d, when λ is the wavelengthof light, and d is the pupillary aperture).

Guyon also investigated the effect of the distance between the center ofthe aperture and the optic axis of the system on the PSF of the opticalsystem, and showed that this parameter could be optimized to provide anoptimum PSF without affecting the net optical transmission of thewavefront through the aperture. Also, the geometry of the inner edge ofthe aperture can further modulate the OTF of the entrance pupil, andthus enhance the OTF of the eye in low to mid spatial frequency region.Even patients with defocus or low order aberrations may benefit from amask with specific edge geometries designed either individually foreach, or for that particular type of vision error. For example, apatient with astigmatism may be fitted with a mask that will have anelliptical shape, with the minor axis of the ellipse matching theastigmatic axis of the patient. In this case, the depth of focus isincreased preferentially along the direction of the astigmatic axis.Such a patient may be able to achieve optimum vision using a sphericalcorrection. The geometry and optical transmission characteristics of theouter edge of the aperture (for an annular aperture) may be designed tominimize the effect of diffraction from this edge.

In Guyon and other astronomical work, phase amplitude variation acrossthe pupillary aperture has been achieved by using mirrors (e.g., thePIAA technique, first proposed by Guyon and Doddier). While suitable forlarger-scale applications such as telescopes, these design solutionscannot readily be adapted to clinical device such as those describedherein.

To achieve some of the features and benefits described herein, it may bepreferable to incorporate a dynamic aperture and/or apodization maskinto a device that may be fixed relative to the pupil. Examples of suchdevices include IOOs, IOLs, corneal inlays, and corneal onlays.Otherwise the effects of the device may be reduced or eliminated, or thedevice may have an undesirable effect on the wearer's vision. Thus, somefeatures described herein may be less desirable for incorporation intodevices that do not remain fixed relative to the wearer's pupil, such ascontact lenses and spectacle lenses.

While illustrative and presently preferred embodiments of the inventionhave been described in detail herein, it is to be understood that theinventive concepts may be otherwise variously embodied and employed, andthat the appended claims are intended to be construed to include suchvariations, except as limited by the prior art.

What is claimed is:
 1. An ophthalmic device comprising: an apodization mask comprising an electro-active, transparent substrate; wherein the substrate has at least one optical transmission property that is alterable by electrical activation.
 2. The device of claim 1, wherein the device is capable of being surgically implanted in a user's eye.
 3. The device of claim 1 wherein, when worn by a wearer, the substrate is fixed in position relative to the wearer's pupil.
 4. The device of claim 1, further comprising a dynamic aperture.
 5. The device of claim 4, wherein at least one the shape of the aperture and the size of the aperture is optimized according to a modulation transfer function of the wearer's eye.
 6. The device of claim 4, wherein the geometry of the aperture is remotely adjustable.
 7. The device of claim 1, wherein the at least one optical transmission property is at least one of the transmitted amplitude and the transmitted phase of light transmitted by the substrate.
 8. The device of claim 7, wherein the apodization mask provides a phase and amplitude profile associated with a retinal image quality for distance vision at an ambient light level range.
 9. The device of claim 1, wherein the at least one optical transmission property is the index of refraction of the substrate.
 10. The device of claim 9, wherein the index of refraction of the substrate in the visual spectrum changes by at least 0.1 units upon electrical activation.
 11. The device of claim 10, wherein the substrate comprises a liquid crystal layer, and the index of refraction of the substrate is alterable by electrical activation of the liquid crystal layer.
 12. The device of claim 11, wherein the liquid crystal layer comprises a guest-host mixture.
 13. The device of claim 11, wherein the liquid crystal layer is homogeneous.
 14. The device of claim 11, wherein the liquid crystal layer is electrically addressable over an area of at least about 0.25 μm2 without affecting the response of adjacent material.
 15. The device of claim 11, further comprising a computerized controller capable of activating multiple segments of the liquid crystal layer.
 16. The device of claim 15, wherein the controller is embedded into the ophthalmic device.
 17. The device of claim 15, wherein the controller is configured to activate segments in a pattern corresponding to a mask that modulates the amplitude, the phase or both the amplitude and the phase of light is transmitted through the device into the eye of a user fitted with the device.
 18. An ophthalmic device, comprising: an apodization mask comprising a transparent substrate; wherein the substrate has at a refractive index gradient of at least 0.01 units/mm in at least one meridian.
 19. The device of claim 18, wherein the refractive index gradient does not affect the level of defocus for light transmitted through the mask.
 20. The device of claim 18 wherein, when the device is worn by a wearer, the substrate is fixed in position relative to the wearer's pupil.
 21. The device of claim 18, further comprising a dynamic aperture.
 22. The device of claim 21, wherein at least one the shape of the aperture and the size of the aperture is optimized according to a modulation transfer function of the wearer's eye.
 23. The device of claim 21, wherein the geometry of the aperture is remotely adjustable.
 24. An ophthalmic device comprising: a substrate; and a liquid crystal layer having a variable optical transmission of about 30%-99% upon electrical activation of the liquid crystal layer.
 25. The device of claim 24, wherein the liquid crystal layer comprises a guest-host mixture.
 26. The device of claim 24, wherein the liquid crystal layer is homogeneous.
 27. The device of claim 24, wherein the device is capable of being implanted into the eye of a wearer.
 28. The device of claim 24 wherein, when the device worn by a wearer, the substrate is fixed in position relative to the wearer's pupil.
 29. The device of claim 24, wherein the liquid crystal layer is electrically addressable over an area of at least about 0.25 μm² without affecting the response of adjacent material.
 30. The device of claim 29, further comprising a computerized controller capable of activating multiple segments of the liquid crystal layer.
 31. The device of claim 30, wherein the controller is embedded into the ophthalmic device.
 32. The device of claim 31, wherein the controller is configured to activate segments in a pattern corresponding to a mask that modulates the amplitude, the phase or both the amplitude and the phase of light is transmitted through the device into the eye of a user fitted with the device. 